The advantages of using blades with a slicing rather than chopping motion have been known for hundreds, perhaps thousands of years. One has but to cut a loaf of bread to immediately realize that a slicing motion cuts cleaner and with less tearing. The most immediate advantage for the blade is the reduction of force that is required for cutting, reducing wear and tear on the cutting edge. For a shaver, it is perhaps more important that the cutting force applied to the follicles be reduced, producing a less painful shaving experience. While it has been possible for the shaver to use straight razors, as well as disposable razor cartridges, in such a way as to create an oblique or slicing angle, this has always been hazardous, as the blade that easily slices follicles also easily slices the epidermis. Several patents have resulted from attempts to safely apply the advantages of a slicing angle to shaving. Gordon, (U.S. Pat. No. 3,964,160) and Copelan, (U.S. Pat. No. 5,526,568) patented razors which made manual oblique shaving easier, that is, the wrist did not have to be held at an awkward angle to maintain the slicing angle, but both lacked the concomitant stability of a razor head perpendicularly oriented to the shaving direction. Copeland teaches that, to obtain the advantages of oblique shaving while avoiding cutting of the skin, the oblique angle of a useable razor head should be restricted to between 10 and 26 degrees, and preferably to an angle of 18 degrees. Razors featuring adjustable slicing angles, such as Gordon's, have had an additional disadvantage, since the geometry of the razor head must be carefully balanced, and is unlikely to be optimum for variable slicing angles. Others have patented a variety of oblique arrangements, wherein a pair of blades are oriented in a "V" arrangement. Carroll (U.S. Pat. No. 1,241,921), Moody (U.S. Pat. No. 228,829), and Browning (U.S. Pat. No. 1,387,465) are typical of this approach, which suffers from excess stability. Because of the large footprint created by the two legs of the cutting zone, such a razor head has great difficulty in handling variations in facial geometry; a difficulty which only increases as the slicing angle, is increased. Savage (U.S. Pat. No. 4,663,843) patented a razor head using a conventional blade in tandem with blades angled at a slicing angle. He teaches that the slicing angle should lie between 15 and 30 degrees, in order to have some of the advantages of oblique cutting, while avoiding cutting of the skin. Savage does not appreciate the advantages arising from the use of intrinsic fencing, which would not only allow shaving at much higher slicing angles, but also make a tandem conventional blade unnecessary.
Fencing of razor blades is known. Dickenson (U.S. Pat. No. 1,035,548) teaches the use of wire wrapping of the blade edges, an approach that has been used by several others, such as Iten (U.S. Pat. No. 3,505,734), and Michelson (U.S. Pat. No. 3,750,285). Similarly, Ferrara (U.S. Pat. No. 3,263,330) discloses a fencing arrangement wherein the blade edge is wrapped with a flexible perforated sheet, and Auton (U.S. Pat. No. 4,252,837) patented a blade fenced with a vacuum deposited intermittent coating. Galligan et al. (U.S. Pat. No. 4,914,817) teaches the use of tape having parallel riblets covering parts of the blade edges.
Cantilever mounting of cutting blades is known. Straight razors and steak knives are to examples. However, none have previously appreciated the advantages accruing to cantilever mounting of intrinsically fenced blades.
Several razors have been patented which featured shaving heads designed to be dynamically flexible in response to various forces exerted during shaving. For example, in Solow, (U.S. Pat. No. 4,754,548), such a razor features a double row of segments equipped with blades, hinged together to allow bending of the razor head. Such a razor has a large footprint, and does not give complete coverage at the end of a stroke. Solow also proposes a single array of angled blade housings, independently mounted to a handle, which is depicted in FIG. 20. This approach suffers from two deficiencies: first, as the razor head is not a single cartridge, it is not easily replaceable, and second, the razor head is subject to considerable chatter, since each of the small razor heads is capable of vibrating relative to its neighbors.
Other examples of dynamic flexibility are found in a patent issued to Motta et al (U.S. Pat. No. 4,443,939). This razor head configuration discloses a razor cap having corrugated segments disposed on either side of the cap center as well as a guard bar which is individually segmented and a seat portion of the blade support structure from which the guard bar depends having a convoluted, cage-like structure. The spacer in this two-blade system has cut out areas to increase flexibility, and blades featuring extended longitudinal slots. Nevertheless, the blade support structure, the blades, the spacer, and the cap must all bend in response to shaving forces, greatly increasing the bending stiffness.
In Chen (U.S. Pat. Nos. 4,854,043 and 4,976,028), a flexible razor head is disclosed which is similar to that of Motta, in that the blade support structure, the blades, the spacer, and the cap must all bend in response to shaving forces.
Each of the razor systems wherein the razor head is moveable suffers from some disadvantage, either from excessive bending stiffness, as in the case of Chen and Motta, or from lack of restraint, as in the case of the single row razor of Solow. None take advantage of the controlled flexibility inherent in oblique cantilevered blades, according to the present invention.